11. Dale's Killer
In the season two episode "Judge, Jury, Executioner", young Carl is wandering alone in the woods with a gun he mischievously acquired when he comes across a Walker stuck in the mud. At first, he simply throws rocks at it but, feeling brave and wanting to bag himself a kill, Carl gets close to the Walker and takes aim with the handgun. The Walker momentarily breaks free, however, and lunges at Carl, spooking him and causing him to flee in terror. This would later come back to haunt him, however, as Dale - who is wandering through the fields to investigate the moans of a dying cow - is brutally attacked by a Walker who tears his intestines out. Daryl stabs the Walker in the head, killing it, and Carl looks at it laying motionless and realises it's the one he opted out of killing earlier.